Optical module and method for manufacturing same

ABSTRACT

The present invention relates to an optical module which can be produced by an easy process and at low cost and a method for fabricating the optical module. An optical module  100  includes a die pad  101 , a plurality of leads  102 , and a first platform  110  and a second platform  120  disposed on the die pad  101 . At least an optical fiber  113  is fixed to a first platform body  111  and at least a light emitter  124  adapted for generating optical signals to be transmitted through the optical fiber  113  is mounted on a second platform body  121.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical module and a method forfabricating the optical module, and more particularly, to an opticalmodule which can be produced by an easy process and at low cost, and amethod for fabricating the optical module.

2. Description of the Prior Art

The advent of the Internet allows one to access and manipulate hugequantities of information in real time. Though copper wire, opticalfiber, wireless means and the like are used to send and receiveinformation, the optical fiber is especially superior for transmittinghuge volumes of information at high speed. Thus, it is expected that theoptical fiber will be extended into every household in the future.

However, when connecting terminal devices by optical fibers, it isnecessary to provide a so-called optical module between the opticalfiber and each terminal device, since terminal devices do not useoptical signals but electric signals for information processing. Theoptical module transforms the optical signals received from the opticalfiber into electric signals and provides the electric signals to theterminal device, and further transforms the electric signals receivedfrom the terminal device into the optical signals and supplies theoptical signals to the optical fiber. Various types of optical moduleshave been proposed in the art.

FIG. 26 is a schematic view showing the structure of a conventionaloptical module.

As shown in FIG. 26, the optical module 10 can transmit and receivesignals in the WDM (wavelength division multiplex) mode. The opticalmodule has a structure wherein a WDM filter 11, a laser diode (LD) 12, aphoto diode (PD) 13 and optical lens 14 and 15 are contained in apackage 16. The WDM filter 11 is an optical filter that passes light ofa predetermined wavelength (for example, about 1.3 μm) used fortransmission and reflects light of a predetermined wavelength (forexample, about 1.55 μm) used for reception, and it is positioned on theoptical path. The laser diode 12 is an element for transforming asupplied electric signal into an optical signal. Light of thepredetermined wavelength of, for example, about 1.3 μm emitted from thelaser diode 12 is supplied to an optical fiber 17 through the opticallens 14 and the WDM filter 11. Light of the predetermined wavelength of,for example, about 1.55 μm supplied from the optical fiber 17 isreflected by the WDM filter 11, after which it is sent to thephoto-diode 13 through the optical lens 15, and is transformed intoelectric signals. It is therefore possible to transform the opticalsignals from the optical fiber 17 and supply them to the terminaldevice, and transform the electric signals from the terminal device andsupply them to the optical filter 17. The above example of the lightwavelengths assumes that the optical module 10 shown in FIG. 26 isinstalled in a terminal device used in a home. If the optical module 10is used on the side of the base station, the wavelengths used fortransmission and reception are reversed.

However, the optical module 10 of the type shown in FIG. 26 requireshigh accuracy in the positioning the individual elements, and, in somecases, fine tuning by a skilled worker. For this reason, there is aproblem that manufacturing efficiency is low, so that the module is notsuitable for mass production.

FIG. 27 is a schematic view showing the structure of anotherconventional optical module.

The optical module 20 shown in FIG. 27 is a so-called optical waveguideembedded type optical module. The optical module 20 comprises asubstrate 21, a cladding layer 22 formed on the substrate 21, coreregions 23 a-23 c formed on a predetermined region of the cladding layer22, a WDM filter 24 inserted in the slot formed on the substrate 21 andthe cladding layer 22, a laser diode 25 provided adjacent to the end ofthe core region 23 b, a photo-diode 26 provided adjacent to the end ofcore region 23 c, and a monitoring photo-diode 27 which monitors theoutput of the laser diode 25. In the optical module 20 of such type, anoptical waveguide constituted by the cladding layer 22 and core region23 a is connected to an optical fiber not shown in the drawing.Accordingly, transmission and reception in the WDM (wavelength divisionmultiplex) mode are performed.

That is, light of the transmission wavelength (for example, about 1.3μm) emitted from the laser diode 25 propagates through an opticalwaveguide consisting of the cladding layer 22 and the core region 23 b,after which it is supplied to the optical waveguide consisting of thecladding layer 22 and the core region 23 a through the WDM filter 24,and enters an optical fiber that is not illustrated. Moreover, light ofthe reception wavelength (for example, about 1.55 μm) supplied from theoptical fiber (not shown) propagates through the optical waveguideconsisting of the cladding layer 22 and core region 23 a, after which itis supplied to the optical waveguide which consisting of the claddinglayer 22 and core region 23 c through the WDM filter 24, and enters thephoto-diode 26. The output of the laser diode 25 is monitored by themonitoring photo-diode 27, and the output of the laser diode 25 cantherefore be optimized.

The optical module 20 of the type described above is smaller than theoptical module 10 of the type shown in FIG. 26, and it has highproductivity because it does not require the fine tuning by a skilledworker. However, there is a problem that it is very expensive and itrequires high connection accuracy between the optical fiber and theoptical waveguide. Thus, an optical module that can be fabricated by aneasy process at low cost is desired.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide animproved optical module and a method for fabricating the optical module.

Another object of the present invention is to provide an optical moduleand a method for fabricating the optical module that can realize lowcost.

A further object of the present invention is to provide an opticalmodule that can be fabricated by an easy process and a method forfabricating the optical module.

According to one embodiment, an optical module comprises a die pad, atleast two platform bodies including a first platform body and a secondplatform body mounted on the die pad, an optical fiber fixed on thefirst platform body, and a light emitter mounted on the second platformbody and adapted for generating optical signals to be transmittedthrough the optical fiber.

According to the present invention, since at least the first platformbody on which the optical fiber is mounted and the second platform bodyon which the light emitter is mounted can be separately fabricated, itis possible to easily design the platform bodies. Further, in the caseof mounting the first platform body and the second platform bodyseparately, since heat generated in the light emitter is not easilytransmitted to the first platform body, it is possible to improve thereliability of the optical module and it is possible to control oftemperature at each step during fabrication of the optical module. Forexample, if the first platform body is mounted after first mounting thesecond platform body and fixing the light emitter and the like, it ispossible to fabricate components on the first platform body free fromthe influence of heat applied when the light emitter and the like arefixed. Furthermore, if the first platform body is mounted after firstmounting the second platform body on the die pad and performing ascreening test, it is not necessary to perform needless processing on aproduct in process that has an initial failure, and it is thereforepossible to reduce manufacturing cost.

Here, the first platform body and the second platform body may bedisposed on the die pad in parallel with each other or the firstplatform body may be placed on the second platform body. In either case,if the first platform body is mounted after the second platform body wasfirst mounted on the die pad and a screening test was performed, it isnot necessary to perform a wasteful process to the product in processwhich has initial failure.

In a preferred aspect of the present invention, the optical modulefurther comprises a receiving photo-diode mounted on the first platformbody and adapted for transforming optical signals received through theoptical fiber into electric signals, and a filter provided so that theoptical fiber is divided at the position between the receivingphoto-diode and the light emitter. The optical module further comprisesa ferrule in which the end portion of the optical fiber is inserted.

In a further preferred aspect of the present invention, the opticalmodule further comprises a monitoring photo-diode which is mounted onthe second platform body and used for monitoring the luminescenceintensity of the light emitter. According to this aspect of the presentinvention, it is not only possible to optimize the luminescenceintensity of the light emitter but also perform the screening testeasily.

In a further preferred aspect of the present invention, the opticalmodule further comprises an encapsulation member which covers at leastpart of the first platform body and the second platform body and part ofthe die pad. According to this preferred aspect of the presentinvention, since the at least two platform bodies mounted on the die padare integrally covered by the encapsulating member, the optical moduleis very easy to handle. Further, since, differently from theconventional optical module, the optical module does not require finetuning by a skilled worker, it has high fabrication efficiency.Moreover, the optical module can be realized at relatively low cost,which is not possible with the optical module including a conventionaloptical waveguide.

In a further preferred aspect of the present invention, the opticalmodule further comprises silicone gel which covers at least part of theoptical fiber, the receiving photo-diode, the light emitter or thefilter. According to this preferred aspect of the present invention, itis possible to protect the optical fiber, the receiving photo-diode, thelight emitter and/or the filter efficiently.

In a further preferred aspect of the present invention, the opticalmodule further comprises at least one IC which receive the outputsignals from the receiving photo-diode and process the output signalsand/or drive the light emitter. In this case, the at least one IC may bemounted on the first platform body or the second platform body, and mayalso be mounted on the die pad.

In a further preferred aspect of the present invention, the opticalmodule further comprises a plurality of leads at least some of which arecovered by an encapsulation member. According to this preferred aspectof the present invention, since the optical module can be mounted on aprinted circuit board similarly to a conventional semiconductor device,the optical module can be easily handled. In this case, the plurality ofleads may be drawn out from a package body consisting of theencapsulation member or may be terminated at a mounting surface of thepackage body. If the plurality of leads are provided so as to beterminated at the mounting surface of the package body, since themounting area of the optical module on a printed circuit board can bereduced, it is possible to produce a much smaller end product.

In a further preferred aspect of the present invention, the die pad islocated at a side opposite to a mounting surface of a package body withrespect to the platform bodies. According to this preferred aspect ofthe present invention, since the die pad located on the upper surfaceside of the package body serves as a heat sink, it is possible to obtaina very high heat radiating property. It is therefore possible to realizeminiaturization of the end product and improved reliability.

Here, the die pad may be provided on a printed circuit board.

The above objects of the present invention can be also accomplished by amethod for fabricating an optical module for transmitting and receivingoptical signals comprising a step of mounting on a die pad a secondplatform body including at least a light emitter which generates opticalsignals to be transmitted, a step of mounting on the die pad or thesecond platform body a first platform body including at least opticalfibers, a receiving photo-diode that performs photoelectric conversionof an optical signal received through the optical fibers and a filterthat separates the optical signal received from the optical signal to betransmitted, and a step of encapsulating the second platform body andthe first platform body with an encapsulation member so that endportions of the optical fibers opposite to the light emitter areexposed.

According to the present invention, since the LE platform body includingthe light emitter and the PD platform body including the receivingphoto-diode and the like are mounted on the die pad and integrallyencapsulated with the encapsulation member, the thus fabricated opticalmodule can be easily handled. Moreover, since, differently from theconventional optical module, the optical module does not require finetuning by a skilled worker, it has high fabrication efficiency and it ispossible to realize relatively low cost, which is not possible with theoptical module including the conventional optical waveguide.

In a preferred aspect of the present invention, the method forfabricating an optical module further comprises a step of mounting thesecond platform body on the die pad, performing a screening test andmounting the first platform body on the die pad. According to thispreferred aspect of the present invention, it is not necessary toperform needless processing on a product in process that has an initialfailure.

In a further preferred aspect of the present invention, the method forfabricating an optical module further comprises a step of applyingsilicon gel to cover at least part of the optical fiber, the receivingphoto-diode, the light emitter or the filter. According to thispreferred aspect of the present invention, it is possible to effectivelyprotect the optical fiber, the receiving photo-diode, the light emitterand/or the filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing the structure of an opticalmodule 100 which is one preferred embodiment of the present invention.

FIG. 2 is a side view schematically showing the structure of a mainportion of an optical module 100.

FIG. 3 is a perspective view schematically showing the structure of afirst platform (PD platform) 110.

FIG. 4 is a perspective view schematically showing the structure of asecond platform (LE platform) 120.

FIG. 5 (a) is a schematic top plan view showing the external appearanceof an optical module 100 and FIG. 5 (b) is a cross-sectional view takenalong a line A-A in FIG. 5 (a).

FIG. 6 is a schematic top plan view showing an optical module 100mounted on a printed circuit board and the like.

FIG. 7 is a diagram showing a step in the fabrication of an opticalmodule 100, preparing of lead frame 105.

FIG. 8 is a diagram showing a step in the fabrication of an opticalmodule 100, pre-mold.

FIG. 9 is a diagram showing a step in the fabrication of an opticalmodule 100, cutting predetermined portions 105 b, 105 c and 105 d of thelead frame 105.

FIG. 10 is a diagram showing a step in the fabrication of an opticalmodule 100, mounting LE platform 120.

FIG. 11 is a diagram showing a step in the fabrication of an opticalmodule 100, mounting PD platform 110.

FIG. 12 is a plan view schematically showing the structure of a mainportion of an optical module 200 which is another preferred embodimentof the present invention.

FIG. 13 is a side view schematically showing the structure of a mainportion of an optical module 200.

FIG. 14 is a plan view schematically showing the structure of a mainportion of an optical module 300 which is a further preferred embodimentof the present invention.

FIG. 15 is a side view schematically showing the structure of a mainportion of an optical module 300.

FIG. 16 is a plan view schematically showing the structure of a mainportion of an optical module 400 which is a still further preferredembodiment of the present invention.

FIG. 17 is a side view schematically showing the structure of a mainportion of an optical module 400.

FIG. 18 (a) is a schematic top plan view showing an external appearanceof an optical module 500 which is a yet further preferred embodiment ofthe present invention and FIG. 18 (b) is a cross-sectional view takenalong a line B-B in FIG. 18 (a).

FIG. 19 (a) is a schematic top plan view showing the external appearanceof an optical module 600 which is a yet further preferred embodiment ofthe present invention and FIG. 19 (b) is a cross-sectional view takenalong a line C-C in FIG. 19 (a).

FIG. 20 is an external view showing one preferred embodiment of anoptical connector including an optical module according to the presentinvention.

FIG. 21 is an external view showing another preferred embodiment of anoptical connector including an optical module according to the presentinvention.

FIG. 22 is a top plan view showing an optical module 800 according to anembodiment in which the PD platform and the LE platform are mounted on aprinted circuit board.

FIG. 23 is a bottom view schematically showing the structure of anoptical module 800.

FIG. 24 is a top plan view showing the resin encapsulated optical module800.

FIG. 25 is a side view showing the resin encapsulated optical module800.

FIG. 26 a schematic view showing the structure of a conventional opticalmodule.

FIG. 27 is a schematic view showing the structure of anotherconventional optical module.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will now be explainedwith reference to the drawings.

FIG. 1 is a plan view schematically showing the structure of an opticalmodule 100 which is one preferred embodiment of the present inventionand FIG. 2 is a side view schematically showing the structure of a mainportion of the optical module 100. Although the optical module 100 ofthis embodiment is ultimately encapsulated and its main portions coveredby a resin, as will be explained further below, FIG. 1 shows the opticalmodule 100 without the encapsulating resin. The region indicated by M inFIGS. 1 and 2 is the region to be ultimately encapsulated.

As shown in FIGS. 1 and 2, the optical module 100 according to thisembodiment has a die pad 101, a plurality of leads 102, a first platform110 and a second platform 120 which are mounted on the die pad 101.

The die pad 101 and the leads 102 are portions formed by cutting oretching a lead frame and are formed of metal. The kind of metal used forforming each of the die pad 101 and the leads 102 is not particularlylimited but it is preferable to form both the die pad 101 and the leads102 of an alloy having excellent electrical conductivity, thermalconductivity, mechanical strength and the like normally used for forminga lead frame, such as an alloy containing copper as a primary componentor an alloy containing iron as a primary component such as 42-alloy(A42). The thickness of the die pad 101 and the leads 102 is set to beas thin as possible so as to ensure the required mechanical strength.The actual thickness thereof is not particularly limited but it ispreferable to form both the die pad 101 and the leads 102 so as to havea thickness of 0.1 mm to 0.25 mm. The area of the die pad 101 isdetermined in accordance with the bottom surface area of the firstplatform 110 and the second platform 120.

The first platform 110 is a platform on which various parts fortransforming optical signals supplied from the optical fiber intoelectric signals are mounted. A perspective view of the first platform110 is shown in FIG. 3.

As shown in FIGS. 1 to 3, the first platform 110 comprises a firstplatform body 111 made of silicon or the like, a groove 112 formed onthe upper surface of the first platform body 111, an optical fiber 113accommodated in the groove 112, a ferrule 114 provided at the endportion of the optical fiber 113, a slit 115 formed on the upper surfaceof the first platform body 111 so as to cross the groove 112, a WDMfilter 116 inserted in the slit 115, a receiving photo-diode 117 and areceiving IC 118 mounted on the upper surface of the first platform body111, and bonding pads 119 formed on the upper surface of the firstplatform body 111, the upper surfaces of the receiving photo-diode 117,the receiving IC 118 and the like. In this embodiment and a followingembodiment, the first platform 110 is sometimes referred to as a PD(photo-diode) platform and the first platform body is sometimes referredto as a PD platform body.

The PD platform body 111 is made of a silicon block or the like. A step111 a is cut at the portion on the PD platform body 111 where theferrule 114 is mounted, and the ferrule 114 is supported by the step 111a. Such a step 111 a can be formed by chemical etching or mechanicaldicing. Although not illustrated, an insulation film coating, such as anoxide film or a nitride film, is also formed on the upper surface of thePD platform body 111. The pad electrodes, wiring and the like connectingwith some of the bonding pads 119, the receiving photo-diode 117 and thelike are provided on the insulation film coating.

The groove 112 is a guidance groove for holding the optical fiber 113.The width and depth thereof are set large enough to accommodate theoptical fiber 113. The groove 112 can also be formed by chemical etchingor mechanical dicing. The optical fiber 113 accommodated in the grooves112 is fixed by an adhesive agent (not illustrated).

As known widely, an optical fiber is a fiber-shaped optical waveguidewhich consists of a core and a cladding surrounding the core, and lightpropagation can be attained by utilizing the difference of theserefractive indexes. The end surface of the optical fiber 113 is madeflat and smooth by polishing.

As known widely, a ferrule has cylinder shape which can hold an opticalfiber. One end portion of the optical fiber 113 terminates inside of theferrule 114. By inserting another optical fiber whose end portion ispolished into the ferrule 114, it is possible to accomplish opticalcoupling between the two optical fibers.

The slit 115 is formed on the upper surface of the PD platform body 111so as to cross the groove 112. The width and depth thereof are setaccording to the size of the WDM filter 116 inserted into it. If thewidth of the slit 115 is wider than necessary, diffraction loss willincrease. Thus, the width of the slit 115 is set only slightly largerthan the thickness of the WDM filter 116. The slit 115 is provided at apredetermined angle so that the light propagating through the opticalfiber 113 from the side of the ferrule 114 reflects at the WDM filter116 and advances in a direction above the upper surface of the PDplatform body 111. The angle of the slit 115 is not particularly limitedbut it is preferably set at an angle of about 30 degree to a planeperpendicular to the upper surface of the PD platform body 111. The slit115 can also be formed by the chemical etching or the mechanical dicing.However, it is preferably formed by mechanical dicing because,differently from the step 111 a and the groove 112, it needs to beformed at the predetermined angle while simultaneously cutting theoptical fiber 113.

The WDM filter 116 is an optical filter which transmits light of thetransmission wavelength (for example, about 1.3 μm) and reflects lightof the reception wavelength (for example, about 1.55 μm). Since the WDMfilter 116 is inserted into the slit 115 formed at the above-mentionedpredetermined angle, it reflects light of the reception wavelengthpropagating through the optical fiber 113 from the side of the ferrule114 upwardly of the PD platform body 111, while it transmits light ofthe transmission wavelength propagating through the optical fiber 113from the side of the LE platform 120 toward the side of the ferrule 114.In addition, the slit 115 into which the WDM filter 116 is inserted isfilled with an optical resin (not illustrated), thus the WDM filter 116is securely fixed by the resin in the slit 115.

The receiving photo-diode 117 is an element that detects light of thereception wavelength reflected by the WDM filter 116 at its bottomsurface and transforms the optical signals into electrical signals. Thereceiving photo-diode 117 is mounted so as to straddle the groove 112 atthe position where a reflective light from the WDM filter 116 can bereceived.

The receiving IC 118 is a device for at least receiving and processingthe output signals of the receiving photo-diode 117. Transfer of thedata between the receiving IC 118 and the receiving photo-diode 117 isperformed through the wiring pattern (not shown) formed on the uppersurface of the PD platform body 111, and transfer of the data betweenthe receiving IC 118 and a terminal device (not shown) is performedthrough the bonding pads 119 or the leads 102. moreover, as shown inFIGS. 1 to 3, if a bonding pad 119 is formed on the photo-diode 117, thetransfer of some of the data or the supply of power between thereceiving photo-diode 117 and the terminal device (not illustrated) canbe performed directly. Although only a single receiving IC 118 ismounted on the PD platform 110 for each transceiver unit in thisembodiment, the number of receiving ICs is not particularly limited andtwo or more ICs may be mounted per transceiver unit. Moreover, it isalso possible to omit the receiving IC 118 if the signal from thereceiving photo-diode 117 is processed by another IC not mounted on thePD platform 110.

The first platform (PD platform) 110 is configured as explained above.

The second platform 120 is a platform on which various components fortransforming electric signals supplied from the terminal device intooptical signals and transmitting them through the optical fiber 113 aremounted. A perspective view of the second platform 120 is shown in FIG.4. FIG. 4 shows the state before mounting the second platform 120 on thedie pad 101, and the optical fiber 113 and the like are not illustrated.

As shown in FIGS. 1, 2 and 4, the second platform 120 comprises ansecond platform body 121 made of silicon or the like, a V groove 122formed on the upper surface of the second platform body 121, a trench123 formed on the upper surface of the second platform body 121 so as tocross the end portion of the V grove 122, and a light emitter 124, amonitoring photo-diode 125, a transmitting IC 126 mounted on the uppersurface of the LE platform body 121, bonding pads 127 formed on theupper surface of the second platform body 121, the upper surfaces of themonitoring photo-diode 125, the transmitting IC 126 and the like. Here,in this embodiment and a following embodiment, the second platform 120is sometimes referred to as an LE (light emitting) platform and thesecond platform body is sometimes referred to as an LE platform body.

The LE platform body 121 is made of a silicon block or the like, as wellas the PD platform body 111. Although not illustrated, an insulationfilm coating, such as an oxide film or a nitride film, is also formed onthe upper surface of the LE platform body 121. Some of the bonding pads127, the pad electrodes, or the wiring connected with some of thebonding pads 127, the light emitter 124 and the like are provided on theinsulation film coating.

The V groove 122 is a guidance groove for correctly aligning the opticalfiber 113 mounted therealong, and the shape thereof is defined so thatthe end portion of the optical fiber 113 faces the light projectingsurface of the light emitter 124 correctly. The V groove 122 can also beformed by chemical etching or mechanical dicing. Chemical etching ismore preferable because it is necessary to position the optical fiber113 correctly.

The trench 123 is provided so as to make the end portion of the V groove122 a vertical plane. This is done because the end portion the V groove122 may become taper-like when the V groove 122 is formed by chemicaletching and in such a case, it becomes difficult to orient the opticalfiber 113 and the light projecting surfaces of the light emitter 124 inthe correct opposing relationship. In order to correctly oppose the endportion of the optical fiber 113 and the light projecting surfaces ofthe light emitter 124, the end portion of the V groove 122 needs to fallin a vertical plane, and in order to realize this, the trench 123 isformed. The trench 123 can also be formed by chemical etching ormechanical dicing.

The light emitter 124 is an element for generating the light projectedinto the optical fiber 113. It can be a laser diode (LD) or a lightemitting diode (LED). The light emitter 124 has two opposing lightprojecting surfaces. One light projecting surface is located on the sideof the V groove 122, and the other light projecting surface is locatedon the side of the monitoring photo-diode 125. Therefore, part of thelight from the light emitter 124 is supplied to the optical fiber 113installed in the V groove 122, and the remainder is supplied to themonitoring photo-diode 125.

The monitoring photo-diode 125 is used to receive the light from theother light projecting surface of light emitter 124 and to monitor itsintensity. The output of the monitoring photo-diode 125 is supplied tothe transmitting IC 126, which optimizes the luminescence intensity oflight emitter 124.

The transmitting IC 126 is a device for receiving at least the signaltransmitted from a terminal device and the output signal of themonitoring photo-diode 125, processing these signals, and driving thelight emitter 124. Transfer of the data between the transmitting IC 126and light emitter 124 or the transmitting IC 126 and the monitoringphoto-diode 125 is performed through the wiring pattern (not shown)provided on the upper surface of LE platform body 121. Transfer of thedata between the transmitting IC 126 and the terminal device (notillustrated) is performed through the bonding pads 127 and the leads102, which are not illustrated. Moreover, as shown in FIGS. 1 and 4, ifbonding pads 127 are formed on the monitoring photo-diodes 125 and thelike, the transfer of some of the data between the terminal device (notillustrated) and the monitoring photo-diode 125 and supply of power canbe performed directly. In addition, although a single transmitting IC126 is mounted on the LE platform 120 for each transceiver unit in thisembodiment, the number of the transmitting ICs is not limited to one butcan be two or more. Moreover, it is also possible to omit thetransmitting IC 126 when the light emitter 124 is driven by another ICwhich is not mounted on the LE platform 120.

The optical module 100 of this embodiment is completed by mounting thePD platform 110 and the LE platform 120 of the foregoing structure inorder on the die pad 101, connecting the bonding pads 119, 127 and theleads 102 by the bonding wires, and encapsulating the area M with resin.

FIG. 5 (a) is a schematic top plan view showing an external appearanceof the optical module 100 and FIG. 5 (b) is a cross-sectional view takenalong a line A-A in FIG. 5 (a).

As shown in FIG. 5 (a) and FIG. 5 (b), the optical module 100 accordingto this embodiment comprises a package body 104 made of resin and havingan approximately rectangular parallelepiped shape, a plurality of leads102 drawn out from both side faces of the package body 104 and bent inthe direction of mounting side 104 a of the package body 104, and twoferrules 114 projecting from a side face different from the side facesthe leads 102 are drawn out from. In other words, the appearance of theoptical module 100 is similar to an ordinary packaged semiconductordevice. For this reason, it can be mounted on a printed circuit boardsimilarly to general semiconductor devices, making it is very easy tohandle.

FIG. 6 is a schematic top plan view showing the optical module 100mounted on a printed circuit board or the like. As shown in FIG. 7, whenan optical module 100 according to this embodiment is mounted on aprinted circuit board or the like, an electrode pattern 31 provided onthe surface of the printed circuit board and the leads 102 of theoptical module 100 are connected electrically and mechanically withsolder or the like, and another optical fiber 32 is fixed by insertioninto the ferrule 114. Thus, the optical module 100 can communicateelectrically with a specified terminal device through the electrodepattern 31 and communicate optically with another terminal through theoptical fiber 32.

Next, a method for fabricating the optical module 100 according to thisembodiment will be explained in detail.

The method for fabricating the PD platform 110 will be explained first.In fabricating the PD platform 110, a block member of silicon or thelike to serve as the PD platform body 111 is first prepared, aninsulation film coating, such as an oxide film or a nitride film, isformed on the upper surface of the block member, electrodes such as thebonding pads 119 and wiring patterns are formed on the insulation filmcoating, and a step 111 a and grooves 112 are formed on the PD platformbody 111 by chemical etching or mechanical dicing. Alternatively, thestep 111 a and the groove 112 may be formed before forming theinsulation film coating, electrodes and the like. Furthermore, theelectrodes may be formed after forming the step 111 a, the groove 112and the insulation film coating.

On the other hand, an optical fiber 113 whose end portions are bothpolished is prepared and one end portion thereof is inserted into andfixed in the ferrule 114. The optical fiber 113 having the ferrule 114at the one end portion thereof is accommodated in the groove 112 andfixed in the groove 112 with an adhesive agent. At this time, as shownin FIG. 3, the optical fiber 113 needs to project only a predeterminedlength from the PD platform body 111.

Next, the slit 115 is formed by chemical etching or mechanical dicing,preferably by mechanical dicing, and the WDM filter 116 is inserted intothe slit 115. And the excess space of the slit 115 is filled withoptical resin, thereby fixing the WDM filter 116 in the slit 115.

Then, the receiving photo-diode 117 and the receiving IC 118 are mountedon the electrode pattern formed on the PD platform body 111. Thus, thePD platform 110 has been fabricated.

Next, a method for fabricating the LE platform 120 will be explained. Infabricating the LE platform 120, a block member of silicon or the liketo serve as the LE platform body 121 is prepared in a manner similar tothe fabrication of the PD platform 110. An insulation film coating, suchas an oxide film or a nitride film, is formed on the upper surface ofthe block member, and electrodes such as the bonding pads 127 and wiringpatterns are formed on the insulation film coating. Then, the V groove122 is formed on the LE platform body 121 by chemical etching ormechanical dicing, preferably chemical etching, and the trench 123 isformed on the LE platform body 121 by chemical etching or mechanicaldicing, preferably mechanical dicing. The V groove 122 and the trench123 may be formed before forming the insulation film coating, electrodeand the like. Furthermore, the electrodes may be formed after formingthe V groove 122 and trench 123, the insulation film coating. However,it is necessary to form the trench 123 after forming at least the Vgroove 122.

Next, the light-emitter 124, the monitoring photo-diode 125 and the ICfor transmission 126 are mounted on the electrode pattern formed on theLE platform body 121. This completes the LE platform 120.

Next, a method for mounting the PD platform 110 and the LE platform 120on the die pad 101 will be explained.

First, as shown in FIG. 7, a lead frame 105 including the die pad 101and the leads 102 is fabricated. Such a lead frame 105 can be producedby punch machining or etching of a metal plate. Next, as shown in FIG.8, the die pad 101 and one tip end portion of leads 102 are connectedwith resin 106, such as PPS (polyphenylene sulfide), and further, eachlead 102 and an outer frame 105 a of the lead frame 105 are connected(pre-molding).

After such pre-molding, the portions 105 b connecting the die pad 101and leads 102, as shown in FIG. 9, the portions 105 c interconnectingthe leads 102, and the portions 105 d connecting the leads 102 and theouter frame 105 a of the lead frame 105 are cut. Thereby the die pad101, the leads 102 and the outer frame of the lead frame 105 areelectrically separated from one another. In this state, since the diepad 101 and leads 102, and further the leads 102 and the outer lead 105a of the lead frame 105, are connected, they are kept in an integratedstate.

Next, as shown in FIG. 10, the LE platform 120 is mounted on apredetermined portion of the die pad 101, and the bonding pads 127 andthe predetermined leads 102 are connected electrically by the bondingwires 103. Next, in this state, an electric signal is transmitted to theLE platform 120 through the leads 102 connected to the bonding wires103, and a screening test is performed. The screening test is a test fordiscovering initial failure of the light emitter 124 by maintainingapplication of a few hundred mA of driving current to the emitters 124for a few hours. By monitoring the intensity of the signal detected withthe monitoring photo-diode 125, it is possible to discover any initialfailure of the light emitter 124. Subsequent fabricating processes areperformed only on products in process that pass the screening test, andno subsequent process is performed on products in process in whichinitial failure of the light emitter 124 was discovered in the screeningtest. It is therefore possible to eliminate pointless processing.

When the screening test is passed, the PD platform 110 is mounted on apredetermined area of the die pad 101 as shown in FIG. 12, and theoptical fiber 113 is arranged along the V groove 122, by which the endportion of the optical fiber 113 is made to face to the light emittingsurface of the light emitter 124 correctly. Next, an adhesive agent 128(see FIGS. 1 and 2) is applied to the optical fiber 113 installed in theV groove 122 and hardened, by which the optical fiber 113 is fixed inthe V groove 122. The material of the adhesive agent 128 is notparticularly limited but a thermosetting resin or ultraviolet-lightcurable resin can be used. Moreover, the optical fiber 113 may be fixedby lids, such as of silicon or quartz, instead of the adhesive agent128.

Next, bonding pads on each platform and predetermined leads 102 areconnected electrically with bonding wires 103, after which silicone gel(not illustrated) is applied onto all optical functional elements, suchas the photo-diodes for reception 117, the light emitter 124 and thelike. Such silicone gel mainly serves to ensure propagation of the lightsignals between the light emitter 124 and optical fiber 113 and as abuffer for protecting the optical functional elements, such as the lightemitter 124 and the like, from mechanical stress from outside. Themechanical stress is absorbed by the silicone gel.

Further, the area M shown in FIGS. 1 and 2 is molded with resin and theleads 102 are cut, by which the optical module 100 is completed.

As described above, since the PD platform 110 and the LE platform 120are mounted on a single die pad 101 and these are encapsulatedintegrally by resin, the optical module 100 of this embodiment can behandled very easily. Further, differently from the conventional opticalmodule shown in FIG. 26, the optical module 100 does not require finetuning by a skilled worker and is therefore high in fabricatingefficiency. It is therefore possible to realize relatively low cost ascompared with the optical module 20 including the conventional opticalwaveguide shown in FIG. 27.

Further, if the LE platform 120 is first mounted on the die pad 101 andthe PD platform 110 is then mounted, the parts on the PD platform 110will not be affected by the heat imparted when mounting the lightemitter 124 and the like on the LE platform body 121. Accordingly, itbecomes easy to control temperature at each process in the fabrication.

Furthermore, in the fabrication of the optical module 100 of thisembodiment, the PD platform 110 is mounted after mounting the LEplatform 120 on the die pad 101 and a screening test is then carriedout. As a result, it is not necessary to perform needless processing ona product in process that has an initial failure, and is thereforepossible to reduce manufacturing cost.

In the above described optical module 100, although the receiving IC 118is mounted on the PD platform body 111 and the transmitting IC 126 ismounted on the LE platform body 121, the IC may be mounted on the diepad 101 in the present invention. Next, an embodiment in which thereceiving IC 118 and the transmitting IC 126 are mounted on the die pad101 will be explained.

FIG. 12 is a plan view schematically showing the structure of a mainportion of an optical module 200 which is another preferred embodimentof the present invention and FIG. 13 is a side view schematicallyshowing the structure of the optical module 200. The optical module 200of this embodiment is finally encapsulated and main portions are coveredwith resin. FIGS. 12 and 13 therefore show the state where the resin isremoved from the optical module 200. Further, the leads and the bodingwires are also omitted from FIGS. 12 and 13.

As shown in FIGS. 12 and 13, the optical module 200 according to thisembodiment has a PD platform 210 and an LE platform 220 which aremounted on a die pad 201, similarly to the optical module 100 accordingto the above embodiment. However, it is different from the opticalmodule 100 according to the above embodiment in the point that thereceiving IC 218 and the transmitting IC 226 are mounted on the die pad201. In other aspects of the configuration of the optical module 200 isthe same as that of the optical module 100.

The optical module 200 according to this embodiment offers the sameadvantages as the optical module 100 according to the above embodiment.Further, since the receiving IC 218 and the transmitting IC 226 are notmounted on a PD platform body 211 and an LE platform body 221 but aremounted on the die pad 201, it is possible to make the PD platform body211 and then LE platform body 221 small. As a result, it is possible toreduce the manufacturing cost as well as the cost of materials, becausea large number of platform bodies 211, 221 can be produced at one timeby cutting a silicon wafer processed in a predetermined manner or thelike into many pieces.

In this connection, in the optical module 200 according to thisembodiment, although the two ICs are mounted on the die pad 201, thenumber of ICs mounted on the die pad may be only one or three or more.Further, a predetermined IC may be mounted on the die pad 201 and theother ICs may be mounted on the PD platform body 211 and/or the LEplatform body 221.

In the above described optical module 100 or 200, both the PD platform110 or 210 and the LE platform 120 or 220 are mounted on the die pad 101or 201. However, in the present invention, the PD platform 110 or 120may be mounted on the LE platform 120 or 220 instead of the die pad 101or 201. Next, an embodiment in which a PD platform is mounted on an LEplatform will be explained.

FIG. 14 is a plan view schematically showing the structure of an opticalmodule 300 which is a further preferred embodiment of the presentinvention and FIG. 15 is a side view schematically showing the structureof the optical module 300. The optical module 300 of this embodiment isfinally encapsulated and main portions are covered with resin. FIGS. 14and 15 therefore show the state where the resin is removed from theoptical module 300. Further, the leads and the boding wires are alsoomitted from FIGS. 14 and 15.

As shown in FIGS. 14 and 15, the optical module 300 according to thisembodiment has a PD platform 310 and an LE platform 320 which aremounted on a die pad 301, similarly to the optical module 100 accordingto the above embodiment. However, it is different from the opticalmodule 100 according to the above embodiment in the point that the PDplatform 310 is not mounted on a die pad 301 but is mounted on amounting region 321 a provided on the LE platform body 321 of the LEplatform 320. In other aspects of the configuration of the opticalmodule 200 is the same as that of the optical module 100.

The optical module 200 according to this embodiment offers the sameadvantages as the optical module 100 according to the above embodiment.Further, since the PD platform 310 and the LE platform 320 aresubstantially integrated, there is an advantage that the positionalrelationship between the light emitter 124 and the optical fiber 113cannot change easily even if the shape of the die pad 301 changesslightly owing to heat stress.

Moreover, although the optical module 100, 200 or 300 has the capabilityto receive optical signal and the capability to transmit opticalsignals, in the present invention, it is sufficient for the opticalmodule to have only the capability to transmit optical signals.

FIG. 16 is a plan view schematically showing the structure of an opticalmodule 400 which is a still further preferred embodiment of the presentinvention and FIG. 17 is a side view schematically showing the structureof the optical module 400. The optical module 400 of this embodiment isultimately encapsulated and its main portions covered with resin. FIGS.16 and 17 show the optical module 400 without the encapsulating resin.Further, the leads and the boding wires are also omitted from FIGS. 16and 17.

As shown in FIGS. 16 and 17, the optical module 400 according to thisembodiment is different from the optical module according to the aboveembodiments only in that it has only the capability to transmit opticalsignals. More specifically, the first platform body 111 is not mountedwith a WDM filter 116, receiving photo-diode 117, receiving IC 118 orthe like and does not include the slit 115 for insertion of a WDM filter116. Further, in this embodiment, no optical fiber accommodated in aferrule 114 is mounted on the first platform body 111 and an opticalfiber wire 413 a is directly mounted on the first platform body 111. Inother aspects of the configuration of the optical module 400 is the sameas that of the optical module 100. The optical fiber is generallyprovided with a coating and a coating 413 b formed on the portion of theoptical fiber 413 projecting from the first platform body 111 remainswithout being removed but the coating 413 b formed on the portion of theoptical fiber 413 mounted on the first platform body 111 is removed.Thus, the optical fiber wire 413 a is fixed in a V groove 412 formed onthe first platform body 111.

The optical module 400 according to this embodiment offers the sameadvantages as the optical module 100, 200 or 300 according to the aboveembodiments even in the case where it does not have the capability totransmit optical signals. More specifically, it is possible to preventthe heat imparted when mounting the light emitters 124 and the like onthe second platform body from affecting the first platform and it isfurther possible to mount the first platform after mounting the secondplatform on the die pad and performing the screening test. Moreover,according to this embodiment, the optical module 400 does not have thecapability to transmit optical signals and the number of components isproportionally fewer, whereby it is unnecessary to accommodate the tipend portion of the optical fiber in the ferrule. As a result, it ispossible to simplify the process for manufacturing the optical module400 and reduce the manufacturing cost of the optical module 400.

Furthermore, the package of the optical module in the present inventionis not particularly limited to the package shown in FIG. 5 and someother package may be adopted. Next, an embodiment in which anotherpackage is adopted will be explained.

FIG. 18 (a) is a schematic top plan view showing an external appearanceof an optical module 500 which is a yet further preferred embodiment ofthe present invention and FIG. 18 (b) is a cross-sectional view takenalong a line B-B in FIG. 18 (a). The optical module 500 according tothis embodiment has the same configuration as that of the optical module100 of the above embodiment except that a package having a differentshape is used. In other words, the optical module 500 has such aconfiguration that the PD platform 110 and the LE platform 120 aremounted on the die pad 101.

As shown in FIG. 18 (a) and FIG. 18 (b), like the optical module 100,the optical module 500 according to the present embodiment comprises apackage body 504 made of resin and having an approximately rectangularparallelepiped shape. However, its leads 502 do not project butterminate at a mounting surface 504 a of the package body 504. Accordingto this embodiment, since the mounting area of the optical module 500 ona printed circuit board or the like is smaller than that of the opticalmodule 100, it is possible to produce a much smaller end product.

FIG. 19 (a) is a schematic top plan view showing an external appearanceof an optical module 600 which is a yet further preferred embodiment ofthe present invention and FIG. 19 (b) is a cross-sectional view takenalong a line C-C in FIG. 19 (a). The optical module 600 according tothis embodiment has the same configuration as that of the optical module100 of the above embodiment except that a package having a differentshape is used. In other words, the optical module 600 has such aconfiguration that the PD platform 110 and the LE platform 120 aremounted on the die pad 101.

As shown in FIG. 19 (a) and FIG. 19 (b), like the optical model 500, theoptical module 600 according to the present embodiment comprises apackage body 604 made of resin and having an approximately rectangularparallelepiped shape and leads 602 which terminate at its mountingsurface 604 a. The reverse face of the die pad 101 is exposed at theupper surface of the package body 604, i.e., the surface on the oppositeside from the mounting surface 604 a of the package body 604. In otherwords, in this embodiment, a portion including the die pad 101, the PDplatform 110 and the LE platform 120 is oriented upside down relative tothe same portion of the optical module 600 and is encapsulated so thatthe bottom face of the die pad 101 is exposed at the upper surface ofthe package body 604.

According to this embodiment, similarly to the optical module 500 of theabove embodiment, it is possible not only to reduce the mounting area ona printed circuit board to smaller than that of the optical module 100,but also to obtain a very high heat radiating property because the diepad 101 exposed at the upper surface of the package body 604 serves as aheat sink. It is therefore possible to realize miniaturization of theend product and improved reliability. In this embodiment, although thebottom surface of the die pad 101 is directly exposed, a heat sink canbe separately provided on the bottom surface of the die pad 101 and heatradiation be conducted through the exposed heat sink.

Next, an optical connector incorporating an optical module according tothe present invention will be explained.

FIG. 20 is an external view showing one preferred embodiment of anoptical connector including an optical module according to the presentinvention. As shown in FIG. 20, the optical connector 700 comprises anoptical module (hidden from view) and a case 701 accommodating theoptical module, and the case 701 has a connecting portion 701 a ofnarrow width. The ferrules 114 project from at the connecting portion701 a. Further, locking portions 702 are formed on both side surfaces ofthe connecting portion 701 a. It is therefore possible to couple theoptical connector optically and mechanically by inserting the connectingportion 701 a of the optical connector 700 shown in FIG. 20 into themating connecting portion of another optical connector (not shown) andfixing the two connectors with the locking portions 702.

FIG. 21 is an external view showing another preferred embodiment of anoptical connector including an optical module according to the presentinvention. As shown in FIG. 21, the optical connector 720 is differentfrom the optical connector 700 shown in FIG. 20 in that its case 721 hasno portion of narrow width and the part from which the ferrule 114projects itself comprises a connecting portion 721 a. It is thereforepossible to couple two optical connectors optically and mechanically byinserting the connecting portion 721 a of the optical connector 720shown in FIG. 21 into a mating connecting portion of another opticalconnector (not shown) and fixing the connectors with the lockingportions 722.

In the present invention, the member on which the PD platform and the LEplatform are mounted is not limited to the die pad of the lead frameinsofar as it is possible to support the PD platform and the LE platformmechanically and to achieve the desired heat radiating property.

FIG. 22 is a top plan view showing an optical module 800 according to anembodiment in which the PD platform and the LE platform are mounted on aprinted circuit board and FIG. 23 is the bottom view thereof. Theoptical module 800 of this embodiment is finally encapsulated and mainportions are be covered by resin. FIGS. 22 and 23 therefore show theoptical module 800 in the state with the resin removed.

As shown in FIG. 22, the optical module 800 according to this embodimenthas a PD platform 110 and an LE platform 120 mounted on a die pad 802formed on a printed circuit board 801. Bonding pads 119 and 127 areconnected to bonding pads 803 formed on the printed circuit board 801through bonding wires 103. The material of the printed circuit board 801is not particularly limited but it is preferably resin or ceramic. Thedie pad 802 and the bonding pads 803 can be formed by metalizing thesurface of the printed circuit board 801. As shown in FIG. 22, it ispossible to form the ferrule 114 so as to project from the printedcircuit board 801.

As shown in FIG. 23, external electrodes 804 connected to correspondingones of the bonding pads 803 are formed on the bottom surface of theprinted circuit 801. When the optical module 100 is mounted on anotherprinted circuit board, electrical connection is established through theexternal electrodes 804. The bonding pads 803 and the outer electrodes804 are connected through internal wiring (hidden from view). Theexternal electrodes 804 can be formed by metalizing the bottom surfaceof the printed circuit.

FIG. 24 is a top plan view showing the resin encapsulated optical module800 and FIG. 25 is the side view thereof. As shown in FIGS. 24 and 25,the surfaces of the die pad 801 and the bonding pads 803 are finallycovered with resin, by which functional portions of the PD platform 110,the LE platform 120 and the like are protected. As shown in FIGS. 24 and25, locking portions 806 are preferably formed on both side surfaces ofthe resin 805. It is therefore possible to couple two optical connectorsoptically and mechanically by inserting the optical module 800 accordingto this embodiment into the mating connecting portion of another opticalconnector (not shown) and fixing the two connectors with the lockingportions 806. Thus, the optical module 800 can be used as an attachableoptical connector by forming the locking portions 806 on both sidesurfaces of the resin 805.

The present invention has thus been shown and described with referenceto specific embodiments. However, it should be noted that the presentinvention is in no way limited to the details of the describedarrangements but changes and modifications may be made without departingfrom the scope of the appended claims.

For example, in the above embodiment, the first platform and the secondplatform are encapsulated in resin. However, the encapsulation materialis not particularly limited and another material may be adopted.

As explained above, since the optical module according to the presentinvention is constituted so that the first platform and the secondplatform are mounted on the single die pad and the respective platformsare independent from each other, the optical module can be easilyhandled. Further, if the second platform is first mounted on the die padand the first platform is then mounted, the first platform will not beaffected by the heat imparted when the light emitters and the like aremounted on the second platform body. Accordingly, temperature can beeasily controlled at each process of the fabrication.

Furthermore, in fabricating the optical module of this invention, if thefirst platform is mounted after mounting the second platform on die padand a screening test is then performed, it is not necessary to performneedless processing on a product in process which has an initialfailure. This also helps to reduce manufacturing cost.

Moreover, since, unlike the conventional optical module, the opticalmodule according to the present invention does not require fine tuningby a skilled worker, it has high fabrication efficiency. In addition,the optical module according to the present invention can be realized atrelatively lower cost than the optical module including the conventionaloptical waveguide.

All of the above U.S. patents, U.S. patent application publications,U.S. patent applications, foreign patents, foreign patent applicationsand non-patent publications referred to in this specification and/orlisted in the Application Data Sheet, are incorporated herein byreference, in their entirety.

From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. An optical module comprising a die pad, at least two platform bodiesincluding a first platform body and a second platform body mounted onthe die pad, an optical fiber fixed on the first platform body, and alight emitter mounted on the second platform body and adapted forgenerating optical signals which should be transmitted through theoptical fiber.
 2. An optical module in accordance with claim 1, whichfurther comprises a receiving photo-diode mounted on the first platformbody and adapted for transforming optical signals received through theoptical fiber into electric signals, and a filter provided so that theoptical fiber is divided at the position between the receivingphoto-diode and the light emitter.
 3. An optical module in accordancewith claim 1, which further comprises a ferrule in which the end portionof the optical fiber is inserted.
 4. An optical module in accordancewith claim 2, which further comprises a ferrule in which the end portionof the optical fiber is inserted.
 5. An optical module in accordancewith claim 2, which further comprises a monitoring photo-diode which ismounted on the second platform body and used for monitoring theluminescence intensity of the light emitter.
 6. An optical module inaccordance with claim 4, which further comprises a monitoringphoto-diode which is mounted on the second platform body and used formonitoring the luminescence intensity of the light emitter.
 7. Anoptical module in accordance with claim 5, which further comprises anencapsulation member which covers at least part of the first platformbody and the second platform body and part of the die pad
 8. An opticalmodule in accordance with claim 6, which further comprises anencapsulation member which covers at least part of the first platformbody and the second platform body and part of the die pad
 9. An opticalmodule in accordance with claim 7, wherein the first platform body andthe second platform body are arranged on the die pad in parallel witheach other.
 10. An optical module in accordance with claim 8, whereinthe first platform body and the second platform body are arranged on thedie pad in parallel with each other.
 11. An optical module in accordancewith claim 7, wherein the first platform body is placed on the secondplatform body.
 12. An optical module in accordance with claim 8, whereinthe first platform body is placed on the second platform body.
 13. Anoptical module in accordance with claim 2, which further comprisessilicone gel which covers at least part of the optical fiber, thereceiving photo-diode, the light emitter or the filter.
 14. An opticalmodule in accordance with claim 5, which further comprises silicone gelwhich covers at least part of the optical fiber, the receivingphoto-diode, the light emitter or the filter.
 15. An optical module inaccordance with claim 2, which further comprises at least one IC whichreceive the output signals from the receiving photo-diode and processthe output signals and/or drive the light emitter. 16.-19. (canceled)20. An optical module in accordance with claim 5, which furthercomprises at least one IC which receive the output signals from thereceiving photo-diode and process the output signals and/or drive thelight emitter.
 21. An optical module in accordance with claim 15,wherein the at least one IC may be mounted on the first platform body orthe second platform body.
 22. An optical module in accordance with claim20, wherein the at least one IC may be mounted on the first platformbody or the second platform body.
 23. An optical module in accordancewith claim 15, wherein the at least one IC may be mounted on the diepad.
 24. An optical module in accordance with claim 20, wherein the atleast one IC may be mounted on the die pad.
 25. An optical module inaccordance with claim 7, which further comprises a plurality of leads atleast a part of which is covered by the encapsulation member.
 26. Anoptical module in accordance with claim 8, which further comprises aplurality of leads at least a part of which is covered by theencapsulation member.
 27. An optical module in accordance with claim 25,wherein the plurality of leads are drawn out from a package bodyconsisting of the encapsulation member.
 28. An optical module inaccordance with claim 26, wherein the plurality of leads are drawn outfrom a package body consisting of the encapsulation member.
 29. Anoptical module in accordance with claim 25, wherein the plurality ofleads terminated at a mounting surface consisting of the encapsulationmember.
 30. An optical module in accordance with claim 26, wherein theplurality of leads terminated at a mounting surface consisting of theencapsulation member.
 31. An optical module in accordance with claim 1,wherein the die pad is located at a side opposite to a mounting surfaceof the package body with respect to the platform bodies.
 32. An opticalmodule in accordance with claim 1, wherein the die pad is provided on aprinted circuit board.
 33. A method of fabricating an optical module fortransmitting and receiving optical signals comprising a step of mountingon a die pad a second platform body including at least a light emitterwhich generates optical signals to be transmitted, a step of mounting onthe die pad or the second platform body a first platform body includingat least optical fibers, a receiving photo-diode that performsphotoelectric conversion of an optical signal received through theoptical fibers and a filter that separates the optical signal receivedfrom the optical signal to be transmitted, and a step of encapsulatingthe second platform body and the first platform body with anencapsulation member so that end portions of the optical fibers oppositeto the light emitter are exposed.
 34. A method of fabricating an opticalmodule in accordance with claim 35, which further comprises a step ofmounting the second platform body on the die pad, a step of performing ascreening test and mounting the first platform body on the die pad. 35.A method of fabricating an optical module in accordance with claim 33,which further comprises a step of applying silicon gel to cover at leastpart of the optical fiber, the receiving photo-diode, the light emitteror the filter.
 36. A method of fabricating an optical module inaccordance with claim 34, which further comprises a step of applyingsilicon gel to cover at least part of the optical fiber, the receivingphoto-diode, the light emitter or the filter.